<?php
header("Content-type: text/css");
$css = file_get_contents('style.css');
if(isset($_GET['scale']) && $_GET['scale']/100 != 1){
    $css = preg_replace_callback('/[\w]+px/', function($match){
        $scale = $_GET['scale']/100;
        $value = (int)substr($match[0], 0, -2);
        return round($value*$scale) . 'px';
    }, $css);
}
print $css;